A pic would help, but if it's a model 71 Mauser, it takes 43 Mauser ammo. AKA 11.15x60R
http://www.buffaloarms.com has brass & dies. So does Grafs.com, and they have cheeper shipping.
If you elect to buy the cheeper Lee dies, save yourself a BIG headache and get an RCBS shell holder at the same time. The Lee shell holder WILL break and soon at that. Mine lasted 9 rounds, and that's over average.
On another forum, 4 fellows related how their Lee shellholder failed on the 1st round!
Buffalo arms sells pre-made bullets, but you can still get a dedicated Lyman mould that throws a 340 grain bullet - or so from grafs or midwayusa,com. With lube, mine weigh 350 grains.
45-90 data is recommended, but 45-70 works just as well. I have used 28.0 grains of accurate arms 5744 withthe Lyman bullet for velocities in the 1500 fps range.
If you go with black or BP sub, just be sure to leave no air gap between powder & bullet and away you go. I tried 777 with a couple .030 Walters veggie wads & no pressure signs or bruised shoulder. The rifle is heavy enough to dampen a lot of the recoil.
I believe you are right about the 10.95 being the actual bore diameter - mine reads 11.05 You can slug the bore to be sure. With a soft lead alloy in your bullets, you should be all right with the same data. Start low to be safe and work up, though.
These are a lot of fun to shoot!
SW